Rubber composition and manufacturing process therefor, and tire

Abstract

A rubber composition that can obtain a rubber elastic body having small rolling resistance and excellent impact resilience and a method for producing the same, and a tire having small rolling resistance and excellent impact resilience are provided. The rubber composition of the present invention is obtained by kneading a rubber component containing a conjugated diene polymer (A) having at least one functional group selected from a tertiary amino group, a thiol group, a hydroxyl group, an epoxy group, a carboxylic acid group, a thioepoxy group, a hydrocarbylthio group and a hydrocarbylsilyl group and a conjugated diene polymer (B) having no functional group chemically bondable to silica, silica (C) and a dispersing agent (D) composed of an organic compound having at least one element selected from the group consisting of nitrogen, carbonyl oxygen and ether oxygen.

1 . A method for producing a rubber composition, the method comprising kneading a rubber component containing a conjugated diene polymer (A) having at least one functional group selected from a tertiary amino group, a thiol group, a hydroxyl group, an epoxy group, a carboxylic acid group, a thioepoxy group, a hydrocarbylthio group and a hydrocarbylsilyl group and a conjugated diene polymer (B) having no functional group chemically bondable to silica, silica (C) and a dispersing agent (D) comprising an organic compound having at least one element selected from the group consisting of nitrogen, carbonyl oxygen and ether oxygen. 
     
     
         2 . The method according to  claim 1 , wherein the dispersing agent (D) comprises an organic compound represented by formula (1) or formula (2):
   A—X—H;   Formula (1)
     M(A′—X—H) n ,  Formula (2)
   
       wherein:
 A represents a group comprising nitrogen and/or oxygen; 
 A′ represents a group comprising nitrogen and/or oxygen; 
 X represents a hydrocarbylene group or a polyoxyalkylene chain each having 1 to 20 carbon atoms, which may be straight-chain or branched; 
 H represents hydrogen; 
 M represents a metal element; and 
 n represents is an integer of 1 to 6. 
 
     
     
         3 . The method for according to  claim 1 , wherein the conjugated diene polymer (B), the silica (C) and the dispersing agent (D) are kneaded, and thereafter, the conjugated diene polymer (A) is added thereto, followed by kneading. 
     
     
         4 . The method according to  claim 1 , wherein the conjugated diene polymer (A), the conjugated diene polymer (B) and the silica (C) are kneaded, and thereafter, the dispersing agent (D) is added thereto, followed by kneading. 
     
     
         5 . A rubber composition obtained by the process of  claim 1 . 
     
     
         6 . The rubber composition according to  claim 5 , wherein the dispersing agent (D) comprises an organic compound represented by formula (1) or formula (2):
   A—X—H;   Formula (1)
     M(A′—X—H) n ,  Formula (2)
   wherein:   A represents a group comprising nitrogen and/or oxygen;   A′ represents a group comprising nitrogen and/or oxygen;   X represents a hydrocarbylene group or a polyoxyalkylene chain each having 1 to 20 carbon atoms, which may be straight-chain or branched;   H represents hydrogen;   M represents a metal element; and   n represents is an integer of 1 to 6.   
     
     
         7 . The rubber composition according to  claim 5 , obtained by kneading the conjugated diene polymer (B), the silica (C) and the dispersing agent (D), and thereafter, adding the conjugated diene polymer (A) thereto, followed by kneading. 
     
     
         8 . The rubber composition according to  claim 5 , obtained by kneading the conjugated diene polymer (A), the conjugated diene polymer (B) and the silica (C), and thereafter, adding the dispersing agent (D) thereto, followed by kneading. 
     
     
         9 . A rubber composition, comprising a rubber component comprising a conjugated diene polymer (A) having at least one functional group selected from a tertiary amino group, a thiol group, a hydroxyl group, an epoxy group, a carboxylic acid group, a thioepoxy group, a hydrocarbylthio group and a hydrocarbylsilyl group and a conjugated diene polymer (B) having no functional group chemically bondable to silica, and at least silica (C) and a dispersing agent (D) comprising an organic compound having at least one element selected from the group consisting of nitrogen, carbonyl oxygen and ether oxygen, which are added thereto. 
     
     
         10 . A tire having a tread obtained from the rubber composition according to  claim 5 . 
     
     
         11 . The method according to  claim 2 , wherein the conjugated diene polymer (B), the silica (C) and the dispersing agent (D) are kneaded, and thereafter, the conjugated diene polymer (A) is added thereto, followed by kneading. 
     
     
         12 . The method according to  claim 2 , wherein the conjugated diene polymer (A), the conjugated diene polymer (B) and the silica (C) are kneaded, and thereafter, the dispersing agent (D) is added thereto, followed by kneading. 
     
     
         13 . The rubber composition according to  claim 6 , obtained by kneading the conjugated diene polymer (B), the silica (C) and the dispersing agent (D), and thereafter, adding the conjugated diene polymer (A) thereto, followed by kneading. 
     
     
         14 . The rubber composition according to  claim 6 , obtained by kneading the conjugated diene polymer (A), the conjugated diene polymer (B) and the silica (C), and thereafter, adding the dispersing agent (D) thereto, followed by kneading.